Bleaching cottons by aqueous solutions of urea peroxide



United States Patent Office BLEACHIN G This application is acontinuation-in-part of application S.N. 804,591, filed Apr. 7, 1959,now forfeited.

The present invention relates to the bleaching of fabric materials andit particularly relates to the bleaching of textile materials.

It is among the objects of the present invention to provide improvedbleaching procedures for various types of textile material, whether inyarn or fabric form, and which may be readily applied, either incommercial application in the dye or bleach house or even in the home.

Another object is to provide new textile bleaching arrangements andoperations which are particularly suited for bleaching cellulosicfabrics which will not undesirably aflfect other types of finishes andwhich will leave the finish in hand unaffected without any decrease instrength or effect upon fabric strength.

Another object is to provide a bleaching system which will be effectiveto bleach various types of finished textile fabrics without affectingthe hand or texture thereof, while at the same time it is possible tocarry out other operations in connection therewith.

Still further objects and advantages will appear in the more detaileddescription set forth below, it being understood, however, that thismore detailed description is given by way of illustration andexplanation only and not by way of limitation, since various changestherein may be made by those skilled in the art without departing fromthe scope and spirit of the present invention.

It has been found that urea peroxide is a most effective bleaching agentfor cotton yarn or cotton fabrics, even if the cotton is mixed withother fibers and even if the cotton has been finished or dyed.

Urea peroxide may be used in relatively small concentrations, rangingfrom .5% to 8% and sometimes as much as 10% of the bath, to giveaparticularly effective whitening or lightening effect, with or withoutthe addition of brighteners or other agents.

It is found that these dilute urea peroxide solutions having a pH of to7, with small amounts of weak acid such as acetic acid may beemployedeven with finished garments, as well as finished fabrics, withoutundesirably affecting the dye or other finish, which may be appliedthereto and with retention of all the quality of the fabric.

The urea peroxide appears to enhance the action of nonionic surfaceactive agents, which may be used in very small quantities or eliminatedwith the urea peroxide accomplishing the lightening or brighteningeffect, with the susbtantially complete removal of soil.

The urea peroxide also may be used with anionic surface active agentswith a great reduction of said anionic agent, particularly Where soap isemployed, without any weakening of the fabric structure.

A particularly unusual effect arises from the great increase in sudsingproperties, which is accomplished even .With poorsudsing detergents ofsynthetic or.soap char- ,acter.

A particularly satisfactory result is that in M1 to /2 of the normalbleaching and washing period a better 3,350,161 Patented Oct. 31, 1967whitening and lightening effect is achieved with substantially completesoil removal.

It has been found that with synthetic fabric and yarn, the sodiumchlorite may be used to achieve most satisfactory bleaching with aminimum of exposure time and to give a particularly satisfactorywhiteness to the fabrics.

The operation may be carried out by beam bleaching in which the beam orlarge spool of yarn is bleached directly, such beam on large spools ofyarn being used for weaving a piece of cloth.

Normally, the beam will contain several hundred pounds of yarn which arebleached in a sealed machine so that the bleached liquor may becirculated throughout the yarn to obtain even bleaching or dyeing.Usually, in beam bleaching about ten to fifteen times as much liquor isutilized in the system as the Weight of the yarn and the percentage ofthe urea peroxide in the bath will vary from 0.2 to 10% based on theweight of the yarn itself.

The urea peroxide bleaching solution may also be used in a beck which isa machine equipped for handling fabrics in a slack rope form so as notto damage or bruise them during bleaching or dyeing.

In a beck, the volume of liquor per weight of cloth runs considerablyhigher than in beam bleaching, with as much as 20 to 30 pounds of liquorbeing used per pound of cloth.

The percentage about 0.2 to 10% being treated.

With such a beck or box machine, patches or small samples of cloth maybe taken out to check the bleaching or depth of shade of the cloth beingprocessed.

These box or beck machines may also be provided with saturators whichare a set of squeeze rolls mounted above the box or beck containing 50to yards of yarn of urea peroxide utilized will again be based upon theweight of the fabric or fabric to make certain that the liquid will bepressed into the interstices. The urea peroxide solution may also beused for bleachmg on a igg.

A jigg is a small batch machine which carries approximately a 500 poundroll of cloth through a solution weighing approximately ten times asmuch as the roll of cloth.

the urea peroxide percentage may vary from 0.2 to 10%.

The jigg machine may be used for a wide variety of fabrics, and thecloth is usually run through the jigg bath from one end of the roll tothe other or end to end.

Frequently, it may be sufficient to provide two ends of the treatment,that is to run the goods twice through the jigg bath from one end of theroll to the other although three, four, or five more'ends may be runeach representing running the goods from one end of the roll to theother.

The same may be done with washing on the jigg where again there may betwo or more ends of wash which means that the 'goods are run from end toend of the wash 3 flowing inside out which means flowing from the centerof the beam through the perforations to the outside of the beam to thepump. Then it may flow outside in with the liquor flowing from theoutside of the beam through the yarn and through the center spindle backto the rear side of the pump.

These inside out and outside in beam bleaching machines are automaticand have automatically actuated reversing valves which change the flowof liquid every few minutes.

In beam bleaching, it is usually desirable to get strings which meansthat strips of the yarn are removed from the beams to check thebleaching and determine whether it is taking place satisfactorily as theurea peroxide is circulated therethrough.

Where urea peroxide is utilized by itself without caustic, it is usuallyunnecessary to neutralize or acidify but where caustic soda is employedto prevent yellowing of the fabric, it is necessary to add acetic acidto neutralize the caustic.

Ordinarily such souring or neutralization may be done with any of thecommon organic acids but acetic acid is preferred since it is leastexpensive and the minimum quantity of the acetic acid is utilized toeffect neutralization and to give a pH of 7.

Where, however, the temperature is elevated giving a likelihood that theacetic acid may be volatilized in neutralizing an alkali, oxalic acidmay be used.

Usually, the urea peroxide and particularly when urea peroxide is usedby itself, the bleaching should take place on the alkaline side at a pHrange of about 8 to 12 and where desirable, an increased temperature maybe employed.

Desirably, with urea peroxide formations, a nonionic detergent should beutilized in amounts of about 2 to together with an optical whitenerparticularly with cellulose fibers inthe same quantities.

These nonionic detergents are particularly useful in beck, beam and jiggbleaching, but with home washing machines, it is desirable to utilizesimilar quantities of anionic detergents.

It is also possible to use a swelling agent where dyestuffs are to beapplied or stripped from the yarn or textile fabric, and these swellingagents may be used either to carry the dye away from the fiber or toapply it to the fiber.

These swelling agents may be used in a smaller quantity ranging from /2to 3%.

Where resinous finishes are used such as to give washand-wear effects,it has been found that the urea peroxide solution also has the effect ofremoving and oxidizing the formaldehyde and eliminating any formaldehydeodor resulting from the treatment with triazone or similar resins.

The urea formaldehyde solution is readily applicable to mixed fabrics.

Typical fabrics which may be treated are rayon-acetate ,suitingsincluding flannel suitings, and in this case, a

combination dyeing and bleaching process may be employed in which theviscose rayon would be dyed black and the acetate would be bleachedwhite.

With rug materials, desirably warm water should be utilized starting ata temperature of 120 F. and gradually increasing to 160 F.

Where the urea peroxide solution is used for home bleaching and washingmachines, it is usually regulated to correspond to the load of fabricsfrom 8 to 10 pounds with an ultraviolet brightener agent being used insmall amounts.

To give a series of examples illustrating the applications of thepresent invention:

EXAMPLE I Bleaching of cotton yarn on beams In the bleaching of cottonyarns on beams, a beam of 253 pounds with 13/1 carded yarn is placed ina machine which is filled with cold water, with the machine first run 5minutes inside-out.

Then the 25% of aqueous detergent solution containing 10 ounces ofnonionic detergent is run 5 minutes outside-in and 15 minutes insideout.

Next there is added a 3% solution containing 7 pounds and 10 ounces ofurea peroxide and a 2% solution containing 5 pounds of caustic sodaflakes run outside-in over a 5 minute period.

The temperature is then raised slightly over a 20 minute period, with aseries of 5 minute runs, the first 5 minute run being inside-out at F.,the second run being for 5 minutes outside-in at F., the next run beingfor 5 minutes inside-out at F. and the last run being for 5 minutesoutside-in at F.

The next succeeding step then involves two successive runs at 180 and a10 minute run inside-out at 180.

Then the machine is drained with a hot running wash being carried on for10 minutes inside-out.

The machine is refilled with hot water at 180 F. and a 0.67% solutioncontaining 2 pounds of acetic acid of 84% concentration is added, with a5 minute run outsidein and a second 5 minute run inside-out.

Then the machine is drained, followed by a cold running wash for 10minutes.

Finally the beam is extracted if it is not to be dyed and any stringsare removed.

This entire operation, which should not take over 90 minutes, will givea very bright, light cotton yarn having a smooth handle and unaffectedas far as strength is concerned, with a saving of time from 2 to 3 ormore hours and with the production of a superior product.

It will be noted that the urea peroxide was only used for about 20minutes to achieve this result, at varying temperatures from 120 to 180,in the presence of caustic soda and with a pH of 8 to 11.

EXAMPLE II Bleaching cotton knit goods with urea peroxide The knit goodsare placed in a bleach tub with a liquor ratio of 20:1 and with allpercentages based on the weight of the goods.

The bath is then boiled for 20 minutes with 5% caustic soda and 3%sodium hydrosulfite, followed by rinsing with warm water. Then the bathis treated for 30 minutes at 180 to with 2% of urea peroxide, 1% ofsodium chlorite and 0.4% of oxalic acid.

Then the pH is adjusted to 10 or above with caustic soda and the bath isrun for 30 minutes longer, followed by rinsing, souring, rinsing, andthen with another run of 20 minutes at 160 F. with 0.025% of anultra-violet brightener.

The resultant knit goods had a superior hand and texture and were not atall unduly affected as, far as strength was concerned.

EXAMPLE III- Treatment of cotton yarn Cotton yarn of the count 8/2 istreated in a liquor ratio of 20:1 with all percentages based upon theweight of the yarn.

The cotton yarn is first run for 30 minutes at 180 to 190 F. with 2% ofurea peroxide, 1% of sodium chlorite and 0.4% of oxalic acid, withoutadjustment of the pH.

Then the pH is adjusted to 10 or above with caustic soda and is run for30 minutes longer, followed by rinsing, sou-ring with acetic acid,rinsing and drying.

This operation saved at least 45 to 90 minutes and produced a superiorcotton yarn.

EXAMPLE IV Treatment of cotton yarn Cotton yarn of the count 14/1 istreated in a liquor The aqueous bath is first run for 30 minutes at 190to 200 F., containing 2% urea peroxide, 2% sodium chlorite, 0.4% oxalicacid, without adjustment of the pH.

Then the pH is adjusted to 11 to 12, with caustic soda and the aqueousbath is run 30 minutes longer.

This is followed by rinsing, souring with acetic acid, and rinsingagain.

Then the bath is run for 20 minutes at 160 F. with 0.2% of anultra-violet whitening agent.

The resultant yarn was of superior quality with a great saving of time.

EXAMPLE V Bleaching of cotton duck Cotton duck in a quantity of 500yards is immersed in an aqueous both containing by volume 1% of ureaperoxide, 1% of 33% aqueous caustic soda solution, Ai% of a nonionicdetergent. The pH was adjusted to 13 and the temperature was adjusted to190 F.

Four ends were run on a jigg for 45 minutes with a running hot waterbath at 160 F. Then the four ends were run through cold water followedby drying.

The duck was bleached to the desired degree of perfection without anychange in its other properties and with no retention of bleaching agent.

EXAMPLE VI Bleaching cotton duck EXAMPLE VII Jigg applications It hasbeen found that urea torily utilized with jiggs.

In a jigg the following aqueous bath is made up, based upon the weightof the goods, containing the following peroxide is verysatisfacingredients Percent Sodium chlorite solution (50%) 1 Oxalic acid0.2 Urea peroxide 1 Caustic soda (100%) 2 Nonionic detergent 0.125

In forming this bath, desirably the nonionic detergent is firstdissolved in 100 gallons at 100 to 110 F., after which the dissolved 50%sodium chlorite solution is added.

The goods are then run one end for 15 to 30 minutes.

Then one-half of the urea peroxide is added, which has been previouslydissolved in warm water and the goods again are run one end and thebalance of the urea peroxide is added.

Then the oxalic acid is added and the temperature is gradually raised to180 F.

The goods are given six ends at 6 minutes per end, after which thecaustic soda previously dissolved is added and the goods are given sixadditional ends.

The bath is then pumped, followed by two ends of hot wash.

Then the bath is dropped, followed by two ends of hot wash, with /2 of56% acetic acid solution.

Finally, the goods are given two ends, are rinsed in the cold, andshelled up.

6 EXAMPLE VIII Beck bleaching of cotton Five thousand yards of 136 x 60combed broadcloth are run on a 15 foot beck with the followingformulation:

Urea peroxide-420 pounds Nonionic detergent--60 pounds 50% aqueouscaustic soda solution In making up the bath, the nonionic detergent andthe caustic soda are added to the beck with gradual heating to 140 F.and while loading.

After heating to 140 F., and after loadingthe becks, the urea peroxideis dissolved in 40 gallons of warm water, and this solution is added.

Then the temperature is raised to 175 F. at a rate of 2 degrees a minuteand the beck is run for 60 minutes and patched.

EXAMPLE IX Bleaching of cotton back fabrics A toy plush fabric having arayon pile and a cotton back, in the amount of 350 pounds of fabricaveraging 1 yard per pound is placed in a dye beck carrying 600 gallonsof water.

The machine is loaded and a nonionic or anionic detergent is added inthe amount of 2% to 3%, based upon the weight of the fabric.

Then a solution of urea peroxide containing 1%. grams per liter,together with a solution of 50% sodium chlorite, containing 1 /2 gramsper liter, is added to give respective concentrations of 3% to 3% of theurea peroxide and the sodium chlorite.

The aqueous bath is then brought to a boil and the 1 gram per liter ofoxalic acid is added to give a 2% concentration of the, oxalic acidfollowed by running for 30 minutes at the boil.

Then 2 gallons of liquid caustic soda of 50% concentration is added,followed by addition of 0.9 pound of optical bleach for the 600 galloncomposition. The bath is then adjusted to a pH of 12 to 13 and is boiledfor 30 minutes.

An excellent bleach was obtained without undesirably affecting the handor quality of the plush and without affecting the strength of the cottonbacking.

EXAMPLE X Bleaching of cotton and synthetic mixtures In the bleaching ofcotton and synthetic mixtures, such as cotton-cotron mixture, a bath ofgallons containing the following additions may be utilized, based uponthe weight of the bath:

Percent Urea peroxide 3 Caustic soda 1 /2 Nonionic detergent /2Chelating agent .05

This bath was maintained at room temperature for one hour and thenelevated to 215 F. for another hour.

A very satisfactory white was produced.

EXAMPLE XI Beck bleaching of synthetic fabrics was added to the beck.Then the temperature was raised to 180 F. and the material was run for30 minutes.

Finally the material was dumped and washed with 3 hot rinses.

EXAMPLE XII White wash laundering One load of 300 pounds of white goodswas processed in a prosperity type stainless steel washer wheel.

The goods were given 3 successive 8 minute suds treatments with flush,soap and draining between the suds treatments. Then 4 suds treatmentsconsisting of 600 cc. of a solution of 4 pounds of urea peroxide and 5gallons of water containing 2 pounds of soda ash.

All of these 4 cycles were run at 150 F., and finally the goods weregiven 4 rinses, 1 at 8 minutes at 180 F. followed by dumping; a secondof 8 minutes at 160 F. followed by dumping; a third at 80 F. followed bydumping; and a fourth of 8 minutes including a blue and sour coldtreatment.

A most satisfactory whitening of the goods was achieved without loss instrength.

EXAMPLE XIII Stripping procedure utilizing urea peroxide It was foundthat material may be stripped and bleached with the use of ureaperoxide. This is accomplished by use of a bath containing 100- parts ofwater in which there are 5 parts of urea peroxide, 5 parts of 50%caustic soda solution, 1 part of a nonionic detergent, and 2 parts of astripping agent.

The fabric, when boiled in such a bath for 30 minutes, resulted instripping the dyestutf and simultaneous bleaching of the fabric.

EXAMPLE XIV Simultaneous bleaching of nylon and acetate tricot with ureaperoxide A tricot fabric composed of nylon and acetate was immersed in abath containing 2 /2 grams per liter of urea peroxide and 2 /2 grams perliter of a 50% compound of sodium chlorite.

The bath was first prepared in the cold and the temperature was raisedto a boil, following which 2 /2v grams per liter of oxalic acid wereadded.

The process was then continued for 35 minutes and the pH was brought upto 9 with tetra sodium pyrophosphate.

Then the bath was run for 30 more minutes and washed A very satisfactorybleach was achieved.

EXAMPLE XV Use of urea peroxide to improve fabric treating with resinfinishing A mixing tank was made up containing 10% of a combination ofresins including 1,000 pounds of triazone resins, 10 pounds of ureaperoxide and 20 pounds of water.

The mixing tank was first charged with the triazone resins, then ureaperoxide was added dissolved in water with 2 parts by weight of waterfor each part by weight of urea peroxide.

The mixture was permitted to stand for 24 hours and it was found thatall free formaldehyde had been removed and the product was free of anyexcess formaldehyde.

EXAMPLE XVI Bleaching of rayon acetate blends In bleaching rayon acetateblends, 2,400 yards of a rayon and acetate flannel suiting fabric anddyed with direct black dye were placed in a 16 foot beck at a 20:1ratio.

aqua ammonia concentration at F.

The bath was then run for 20 minutes and the fabric was washed.

The acetate rayon was of a highly improved white and sodiumhydrosulphite was not required.

EXAMPLE XVII Bleaching rug material Rug material was bleached in apaddle machine with a 20:1 liquor ratio. The following percentages wereadded, based upon the weight of the goods, namely:

Percent Caustic soda 5 Urea peroxide 5 Nonionic detergent 1.25

The goods were wet out for 5 minutes in warm water containing thenonionic detergent.

Then the urea peroxide was added, dissolved in warm water and the masswas run for 5 minutes. Then a solution of caustic soda was added and thetemperature was gradually raised from 140 to F. and run for 30 minutes.

The bath was dropped and the goods were given a hot running rinse andthen soured in 0.25 acetic acid. The fabric was finally rinsed in coldrunning water and finished.

This treatment is particularly satisfactory for rayon material in apaddle machine.

EXAMPLE XVIII Laundry bleach procedures To give a laundering bleachprocedure which may be used domestically or in commercial laundries, acombination may be made up of:

3% by weight of urea peroxide .25 of acetanilide .25 of ultra-violetbrightening agent 96.5% of water at room temperature with the pH beingadjusted to 5.0 to 5.5.

It was found that a solution of this concentration may be mostconveniently added in the amount of 6 ounces to a 30 to 50 pound load.

This solution will not harm fast colors and will give white goods anenhanced brightness 'and is particularly adapted to wash and wear andmixed fabrics containing cotton, wool, nylon and Dacron. The mixture maybe added to with a regular detergent or soap without affecting thedetergent actionI This type of solution may also be very effectivelyused for removing stains and spots on fabrics upon being 10- callyapplied, followed by using a regular laundering operation.

As many changes could be made in the above bleaching procedures, andmany widely different embodiments of this invention could be madewithout departure from the scope of the claim, it is intended that allmatter contalned in the above description shall be interpreted asillustrative and not in a limiting sense.

Having now particularly described and ascertained the nature of theinvention, and in what manner the same is to be performed, what isclaimed is:

A process of bleaching cotton duck which comprises treating it in anaqueous bath containing by volume 1% of urea peroxide, and 1% of 33%aqueous caustic soda at a pH of 13 and a temperature of F.

(References on following page) 9 10 References Cited OTHER REFERENCESUNITED STATES PATENTS Baier: Alien Prop. Cust. No. 250,850, pub. July13,

=8/19'12 Stanek 260-553 1943- 7/1928 Jones. 10/1933 Lehner et a1. 8 1105 I. TRAVIS, BROWN, Acting Primary Examiner. 4/1939 Frenkel 8111 XMORRIS O. WOLK, NORMAN G. TORCHIN, 2/1946 Woodhouse et a1. 8-110 XExaminers.

F. CACCIAPAGLIA, H. WOLMAN, I

FOREI N PATENTS Assistant Examiners.

3/ 1942 Germany. 0

